Copying material employing fluoran color formers

Abstract

Fluoran compounds of the formula ##STR1## wherein one of R 1 , R 2 , R 3 and R 4 represents n-alkyl having 6 to 12 carbon atoms and the other R's, independently of each other, represent hydrogen, alkyl having 1 to 12 carbon atoms, alkoxyalkyl having 2 to 8 carbon atoms or benzyl optionally substituted in the ring by nitro, halogen or alkyl having 1 to 6 carbon atoms. The fluoran compounds are particularly useful as color formers which give intense dark green color when they are brought into contact with an electron-accepting co-reactant.

We claim: 
     
       1. A pressure-sensitive copying material containing a support coated with a color forming fluoran compound of the formula ##STR17## wherein R 1  and R 2  represent alkyl of 1 to 4 carbon atoms, R 3  represents n-alkyl of 8 to 12 carbon atoms and R 4  represents hydrogen, n-alkyl of 6 to 12 carbon atoms or benzyl. 
     
     
       2. A pressure-sensitive copying material according to claim 1, comprising said color forming fluoran dissolved in an organic solvent, and said material also comprising a solid electron accepting substance. 
     
     
       3. A pressure-sensitive copying material according to claim 2, wherein the solid accepting substance is attapulgus clay, silton clay, silica or a phenol-formaldehyde resin. 
     
     
       4. A pressure-sensitive recording material according to claim 1, wherein the fluoran compound is encapsulated in microcapsules. 
     
     
       5. A pressure-sensitive copying material according to claim 4, wherein the encapsulated colour former is coated on the back side of a transfer sheet and the electron accepting substance is coated on the front side of a receiving sheet. 
     
     
       6. A process for making copies with a pressure-sensitive copying material, wherein said material is a copying material according to claim 1. 
     
     
       7. A thermoreactive copying material having a support coated with at least one binder layer and containing an electron accepting substance and a color forming fluoran compound of the formula ##STR18## wherein R 1  and R 2  represent alkyl of 1 to 4 carbon atoms, R 3  represents n-alkyl of 8 to 12 carbon atoms and R 4  represents hydrogen, n-alkyl of 6 to 12 carbon atoms or benzyl. 
     
     
       8. A thermoreactive copying material according to claim 7, which contains the fluoran compound and the electron accepting substance in at least one binder layer on paper.